Show HN: Building a GPS receiver https://ift.tt/vdZ2FhV

Show HN: Building a GPS receiver Hi everyone! Shortly after publishing my iOS 4 jailbreak last October[1], I got to work on my next hobby project: a from-scratch homebrew GPS receiver, which can solve the user’s location solely from billions of radio antenna samples. I took a commodity SDR (alongside the Python standard library and numpy) and built a signal processing pipeline that can detect and track GPS satellites over many minutes, drop and pick up satellites as they come in and out of view, and precisely determine the user’s position and clock inaccuracy. All told, gypsum can go from a cold start to a fix on the user’s position, and the precise time, in less than a minute of listening to the antenna. I went on a journey of learning how to detect and track satellite signals that are literally too quiet to hear, and I hope that some of the magic comes through in the posts! After implementing this myself and walking the long road of getting it working, I’m left completely stunned by the brilliance of GPS, across so many axes. I hope you enjoy the read! On a more personal note, I’ll be starting a new job next week which isn’t as amenable to publishing side projects, and therefore this will be my last publicly-published project for some time. I’ve had great experiences making and sharing projects on here, and I’m really grateful for the positive feedback that’s been shared! [1]: https://ift.tt/cyBsAGd https://ift.tt/LFDmJu7 April 15, 2024 at 08:12PM

Help Us Beautify Geary – and Learn the Latest on the Corridor’s Transit and Safety Upgrades

Help Us Beautify Geary – and Learn the Latest on the Corridor’s Transit and Safety Upgrades
By David Sindel

A 38 Geary bus beats traffic in the new transit lanes installed last fall.

The Geary Boulevard Improvement Project aims to address bus delays and traffic concerns on a high-injury corridor. Community feedback played a major role in the transit and safety improvements we’re bringing to Geary. 

As we share the latest on these upgrades, we invite you to weigh in on a new topic: beautification. 

Join us Wednesday, April 17 for an open house about community enhancement for the Geary Boulevard Improvement Project.  

Date/time: Wednesday, April 17, 2024 from 5 - 7 p.m. 

Location: Presidio Middle School Library – 450 30th Avenue, 2nd floor 

Selecting the best option to beautify Geary 

At the open house, drop in to learn more about seven options to beautify Geary Boulevard. They include:  

• Sidewalk pavers 

• Etched/stamped sidewalk concrete 

• Decorative sidewalk concrete with glass aggregate 

• Street trees 

• Leaning rails at bus stops 

• Large district marker 

• Small neighborhood identity markers 

You can see examples and more information on our Geary Boulevard Improvement Project Community Enhancement webpage. 

Some of these options provide the opportunity to highlight the Richmond District’s rich history and/or culture. Others contribute to neighborhood identity or place-making. For example, decorative sidewalk designs at bus stops could highlight local culture. Or, a large district marker could pay homage to the surrounding architectural styles. New street trees could spruce up the boulevard. Sidewalk pavers could add to its character. 

Photo on left shows an example of a district marker; upper right shows etched concrete; lower right a concrete and glass treatment.

Welcoming feedback online or in person 

You can take the Geary Boulevard Improvement Project Community Enhancement Survey now.

You can also attend the open house on April 17 to learn more, chat with staff and submit your survey in person. We look forward to your feedback! 

We will have a second round of outreach later this year. At that time, we’ll share the favorite treatment(s) and ask for feedback on the details of the design. Crews will install the selected treatment during the construction phase of the project. This stage includes other planned utility, transit, safety and pavement improvements. 

People board at a Geary 38 stop that was relocated to help improve travel times.

Improving bus travel times with Quick-Build work 

As we welcome new ideas for beautification, we’re proud to share an early win for the corridor. 

We recently completed implementation of the “Quick-Build” phase, which included new transit lanes between 15th and 28th avenues. It also included bus stop changes to improve reliability of Muni’s 38 Geary line and safety treatments. Preliminary results already show improved bus travel times for over 40,000 daily riders. Muni operators say the changes are helping. We plan to publish a full evaluation report later this year.

Finding creative ways to support businesses 

We also devoted project funding to support local businesses. Our goal: find creative ways to attract customers to the corridor. 

To make this happen, we're convening a Geary Small Business Working Group. Our project team is working to execute the group's priorities: 

• Wrap Geary Boulevard tree trunks with decorative lighting 

• Create an ad campaign on Muni buses to promote the Central Richmond 

Preparing for the next steps: utility upgrades, then transit and safety work 

Starting in early 2025, SFPUC will begin upgrading the sewer and water lines along Geary. For more information, you can visit the SFPUC’s Geary Boulevard Sewer and Water Improvements project webpage. 

Additional transit and safety improvements will begin in 2026. During this stage, we will install the selected community enhancement. 

This construction phase will also include: 

• Bulb-outs to expand passenger waiting areas 

• Pedestrian bulb-outs and median refuges to make crossing Geary Boulevard safer 

• Upgrades of aging traffic signals 

After the entire project corridor is freshly repaved, crews will also paint transit lanes red. 

You can learn more about the project and subscribe for updates by visiting the Geary Boulevard Improvement Project page (SFMTA.com/Geary). 

Published April 16, 2024 at 03:07AM
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Show HN: Docker-boot – Run a system from RAM without LiveCD https://ift.tt/yrzRbqZ

Show HN: Docker-boot – Run a system from RAM without LiveCD How often do you screw up the system so much you have to reformat the disk (without losing data) to fix it? Well, sometimes I do, and sometimes I can't be bothered to burn a live ISO onto a USB stick. There's initramfs, but it's hardly a pleasant environment, with network configuration and all. My go-to solution has typically been to create a chroot with busybox and a few utilities in /tmp, chroot into it, and then kill services that use the solid drive so that I can unmount it. That's an error-prone process, and sometimes systemd itself uses disk, so you can't unmount the drive despite killing all the userland but PID 1. This script improves the UX. It uses a Docker image as the chroot base, which is much easier to tailor to your needs, and automagically commits all the atrocities, such as tearing down all the userland processes, including PID 1, and re-spawning the host system from the container filesystem. It also drives libostree and Nix users mad, because it can be used to try out a new DE or even a whole OS without polluting the host filesystem or spawning a virtual machine. The video in the README shows me trying out KDE + SDDM from a host running GNOME + GDM3. https://ift.tt/T5knNQ9 April 14, 2024 at 11:08PM

Show HN: I built Stack, the open-source Clerk/Firebase Auth alternative https://ift.tt/hXsbpkH

Show HN: I built Stack, the open-source Clerk/Firebase Auth alternative https://ift.tt/eUv6aZG April 14, 2024 at 07:30PM

Show HN: GPU price-per-hour tracker for A100/H100s https://ift.tt/s7pkbRg

Show HN: GPU price-per-hour tracker for A100/H100s Out of curiosity, I put together a simple website which tracks the prices for a few variations of A100/H100 GPUs by hour broken out between spot/ondemand, form factor and provider. Specifically I was tailoring the tool towards the smaller, emerging providers like runpod, gpulist.ai, lambda labs etc. Anyone have any ideas to expand/refine it? https://ift.tt/yV3qGS6 April 14, 2024 at 12:38AM

Show HN: ZSV (Zip Separated Values) columnar data format https://ift.tt/KVZI8Ez

Show HN: ZSV (Zip Separated Values) columnar data format A columnar data format built using simple, mature technologies. https://ift.tt/HQq4IyX April 14, 2024 at 01:22AM

Show HN: My $1k self-install, off-grid solar backup build for renters https://ift.tt/X4rMyk9

Show HN: My $1k self-install, off-grid solar backup build for renters https://sunboxlabs.com April 14, 2024 at 12:29AM